Cushioned valves



Dec. 8, 1959 E. c. MURPHY 2,916,019

CUSHIONED VALVES Filed Aug. 3Q. 1955 United AStates Patent cUsHIoNED vALvEs Edward C. Murphy, Indianapolis, Ind., assignor to Western Electric Company, Incorporated, New York, N.Y., a corporation of New York Application August 30, 1955, Serial No. 531,491

1 Claim. (Cl. 121-465) This invention relates to cushioned valves, and more particularly to cushioned hydraulic valves.

In the use of valves of a type having piston-type plungers with high pressure hydraulic liquids, as the plunger is shifted to the position toward which it is being moved, sometimes both hydraulic and mechanical shocks occur. Breakage and high maintenance costs result from such pounding. Hitherto, there has been no simple, effective dashpot structure for eliminating such shocks.

An object of the invention is to provide new and improved cushioned valves.

Another object of the invention is to provide new and improved cushioned hydraulic valves.

Another object of the invention is to provide hydraulic valves having sleeve inserts for cushioning plungers thereof.

, A further object of the invention is to provide hydraulic valves of a type having plungers movable by high actuating forces during shifting movement thereof and provided with internal dashpot sleeves into which portions of the plunger move to dam-p movement thereof.

A cushioned valve illustrating certain features thereof may include a ported valve housing and a plunger movable therein to change the condition of the valve. A cup located in the housing at one end of `the path is entered by a portion of the plunger having a slight clearance relative thereto to provide a dashpot effect with that portion of the plunger, thereby preventing pounding by the plunger as it reaches the end of its travel.

A complete understanding of the invention may be obtained from the following detailed description of a valve forming a specific embodiment thereof, when read in conjunction with the appended drawing, in which the.

single figure is a longitudinal section of a valve forming one embodiment of the invention. 4

Referring now in detail to the drawing, there is shown therein a cushioned hydraulic valve of the four-way type having a cylindrical housing or body having a centrally located inlet port 11 leading from a source of hydraulic liquid under pressure and which may be selectively connected by a plunger 12 to an outlet port 13 and an outlet port 14. Exhaust ports 15 and 16 at the ends of a bore 17 in the housing lead to a common exhaust passage 18 leading to a supply tank (not shown), or the like, for the pressure source and under much lower pressure than the pressure on the liquid supplied to the supply port 11.

Flanged guide bushings 21 and 22 are bolted to the ends of the housing 10 and have seals 23 and 24 of well known types. The bushings guide a pair of rod portions 25 of the plunger 12, and have cups or sleeves 27 and 28 projecting from the ends thereof. The sleeves are provided with counterbores 31 and 32, which t with a slight clearance of a few thousandths of an inch around collar portions 33 and 34 of the plunger 12. This clearance is sufficiently great that oil or hydraulic liquid ows into the counterbores 31 and 32 under normal exhaust presv 2,916,019 PlatentedvsDec. v 8, 1959 ice sures to keep these counterbores lled with liquid and are suticiently` small that when the plunger 12 is shifted so that lone ofthe collar portions is moved farther into the sleeve 27 or 28 by a solenoid winding 41 or a solenoid winding 42, the oil is permitted to escape only slowly so that the movement of the plunger 12 is damped. A clearance found to be very satisfactory when used with conventional hydraulic uid used in injection molding presses is in the order of 0.0025 of an inch, the collar portions having a diameter in the order of one inch in this instance.

It should be noted that the sleeves 27 and 28 are so positioned that the collar portions 33, 34 enter the sleeves a substantial distance before one of the ports 13 and 14 is opened to the high pressure supply port 11 so that hydraulic shock is eliminated. The damping action of the sleeves 27 and 28 is such that whenever one of the ports 13 and 14 is opened to the port 11 by movement of a piston 45 or a piston 46 of the plunger 12, the opening between the ports 11 and 13 or 14 is made sufficiently slow so as to avoid hydraulic shock to the equipment and lines connected to the housing 10. That is, the pressure of liquid in the ports 13 and 14 is prevented from changing abruptly by means of the damping action of the sleeves 27 and 28 and the collar portions 33 and 34. Also, the damping force is increased as either collar portion moves farther into its sleeve due to the lengthened escape path from the counterbore 31 or 32. This prevents shock between the collar portion and the sleeve 27 or 28 as the plunger 12 reaches the end of its movement, a-t which time the pull of the solenoid winding 41 or 42 is high on core portion 51 or 52. This damping toward the end of the movement can be increased by tapering either the collars or the counterbores in such a way as to reduce the clearance between the collars. and the counterbores as the plunger approaches the end of its movement.

Opposed springs 53 and 54 are enclosed in tubular sleeves or housings 55 and 56, and hold the plunger 12 in neutral position when neither of Ithe windings 41 and 42 is energized.

The above-described valve eliminates hydraulic shocks and mechanical shocks from changing its condition. Its construction is simple and durable and is inexpensive both in original and maintenance costs.

It is to be understood that the above-described arrangements are simply illustrative of the application of the principles of the invention. Numerous other arrangements may be readily devised by those skilled in the art which will embody the principles of the invention and fall within the spirit and scope thereof.

What is claimed is:

A hydraulic valve, which comprises a body member having a cylindrical chamber formed therein, said body member having a pair of sp-aced outlet ports and an interposed inlet port communicating with said chamber, a plunger mounted in said chamber, a pair of spaced pistons on said plunger adapted to cover both said outlet ports, said plunger extending beyond said pistons to provide a pair of collars, said collars having rod-like projections slidably mounted in opposite extremities of said body member, said inlet port being supplied with uid under pressure to fill said cylinder and position said pistons to cover said outlet ports, a pair of cup-like members extending from opposite extremities of said chamber into juxtaposition with the ends of said collars, said cup-likev members being provided with bores tapering in diameter in directions away from the ends of said collars, said collars having diameters slightly less than the minimum diameters of the bores, said members having an exhaust passage filled with lluid communicating with the chamber at the extending portion of said cup-like members for recontinual-'1y increasing force opppsingrmoyement Qfsaid 5 piston corllarvin proportion to the `tapering diameter of said eup-like member. l:

References Cited i'n the leof this patent UNITED STATES PATENTS Garrison Sept. 26, 1882 Jordan Apr. 9, 1929 Foster Feb. 7, 1939 Emst 'f..' 111116 17,

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